Doubts grew on Monday about the validity of trades in the turmoil that followed this month's removal of the cap on the Swiss franc, with administrators of Alpari UK saying they were taking another look at the retail broker's trades. Clients of fellow broker IG Group (IGG.L), meanwhile, have told Reuters they are considering ways to challenge losses made during a financially crippling few minutes immediately after the freeing up of Swiss franc rates on Jan. 15. Moves of up to 40 percent in the franc's value meant that the scale of losses depended heavily on where on the way down investors managed to complete automatic ... (full story)